Month: August 2020

Hermes Lite v2 a 5w SDR

The Hermes-Lite is a low-cost direct down/up conversion software defined amateur radio HF transceiver based on a broadband modem chip and the Hermes SDR project. It is entirely open source and open hardware, including the tools used for design and fabrication files.

Hermes Lite V2 SDR

The SDR is controlled over your LAN, and plugs into your router. This can provide both local and remote operation. You can read more online about the project on the Hermes website.

The board comes fully installed, although you do need to follow the instructions on thermal dissipation for the PA. The radio will deliver 5w and is suitable for all modes and works particularly well on digital modes.

The microphone can be plugged into your PC, and then defined as the soundcard on the radio. In this audio clip, you can hear Gerald G4AXP (40w), and M0TAZ (5w) both using Hermes Lite SDR to have a chat on 5 MHz. In this case, I was using a cheap USB headset as I find headphones often help with noisy HF bands.

M0TAZ 5w and G4AXP 40w both using Hermes Lite SDR radios

The example RX filter setup in Spark SDR shown here.

The radio needs to be controlled by software locally installed on your PC, and you have a wide choice. I started with SparkSDR, as this program has a number of really neat features. The ability to have 4+ receivers running decoding digital modes on the fly. You will find SparkSDR have a online forum for questions and support.

Decoding 4 bands FT8 simultaneously

Here we will look at the setting to use Spark SDR with WSJT-X, setting up the sound card option, and radio mode set to DIGIU and hamlib.

You can use VAC to feed another digital program
Audio Settings
Enable Rigctl CAT
General setting page

In WSJT-x you need to set the rig to Hamlib NET rigctl and Network Server to your local IP address of the PC using port 51111

Network Server to PC IP address port 51111

Here we see WSJTx configured with SparkSDR and Hermes receiver decoding FT8

Its possible to do FT8 and other digital modes directly in SparkSDR, you dont even need to VAC but its good to have control as we can use this with other programs.

SparkSDR can be integrated with FLdigi using Hamlib

I have been running the Hermes Lite now for a few days. 140 QSO most FT8 or FT4 between 3 to 5w. This reception report is amazing, not worked but nice to know you have potential. ZL4AS